Herbicidal composition and method of controlling weeds

ABSTRACT

A herbicidal composition comprising at least one compound of formula I ##STR1## R 2  is methyl, methoxy or --OCHF 2 , R 3  is methyl or --OCHF 2  and 
     E is ═C-- or ═N--, with E being ═N-- when R 2  is methoxy, 
     or an agrochemically acceptable salt of at least one of the compounds of formula I, and a compound of formula II ##STR2## or an agrochemically acceptable salt of the compound of formula II and/or III, in admixture with one another.

This Appln is a 371 of PCT/EP96/00398 filed Jan. 31, 1996.

The present invention relates to a novel herbicidal compositioncomprising a herbicidal active ingredient combination that is suitablefor the selective control of weeds in crops of useful plants, forexample in crops of cereals, rape, sugar beet, sugar cane, plantationcrops, rice, cotton and especially maize and soybeans.

The invention relates also to a method of controlling weeds in crops ofuseful plants and to the use of the novel composition for that purpose.

The compounds of formula I ##STR3## R₂ is methyl, methoxy or --OCHF₂, R₃is methyl or --OCHF₂ and

E is ═CH-- or ═N--, with E being ═N-- when R₂ is methoxy,

and salts thereof, have herbicidal action. This is described, forexample, in EP-A-84 020, EP-A-496 701 and EP-A-120 814.

The following compounds of formulae II and III ##STR4## and theiragrochemically acceptable salts, especially the alkali metal, ammoniumand amine salts, are likewise known as herbicides(gluphosinates andglyphosates), for example in the "The Pesticide Manual", Tenth Edition1994, Crop Protection Publications, and are also commercially available.

It has now surprisingly been found that a combination of variableproportions of at least one of the compounds of formula I with one ofthe above-mentioned compounds of formula II and/or III produces aherbicidal action that is capable of controlling the majority of theweeds that occur especially in crops of useful plants, pre-emergence andespecially also post-emergence, without any significant damage beingdone to the useful plant.

There is therefore proposed in accordance with the present invention anovel composition for the selective control of weeds which, in additionto customary formulation adjuvants, comprises as active ingredient atleast one compound of formula I ##STR5## --OCHF₂, R₃ is methyl or--OCHF₂ and E is ═CH-- or ═N--, with E being ═N-- when R₂ is methoxy, oran agrochemically acceptable salt of at least one of the compounds offormula I, and a compound of formula II ##STR6## or an agrochemicallyacceptable salt of the compound of formula II and/or III, in admixturewith one another.

Examples of agrochemically acceptable salts of the compound of formula Iare given in the afore-mentioned EP-A-84 020, EP-A-496 701 and EP-A-120814, in each case on page 4. The amines described therein and alsoalkali metal hydroxides and ammonium hydroxide are likewise examples ofsuitable salt-forming agents for the compounds of formulae II and III.

The herbicide mixture according to the invention can be used against alarge number of agronomically important weeds, such as Veronica, Galium,Papaver, Solanum, Chenopodium, Amaranthus, Xanthium, Abutilon, Ambrosia,Sagitaria, Ipomoea, Cassiastora, Datura stramonium, Sesbania exaltataand Sida spinosa, in crops of useful plants, especially in crops ofmaize and soybeans.

The compositions according to the invention are suitable for all methodsof application customary in agriculture, for example pre-emergenceapplication, post-emergence application, which is preferred, and seeddressing.

The herbicide mixture according to the invention is suitable especiallyfor controlling weeds in crops of useful plants such as cereals, rape,sugar beet, sugar cane, plantation crops, rice, cotton and especiallymaize and soybeans.

Crops are to be understood as including those crops which have been madetolerant to herbicides or classes of herbicide, for example toglyphosates or gluphosinates, by conventional methods of breeding orgene technology.

The active ingredient combination according to the invention comprisesthe compound or compounds of formula I and the compound of formula IIand/or III in any desired mixture ratio, generally with an excess of onecomponent over the other. Preferred mixture ratios between thecompound(s) of formula I and the mixing partner(s) of formula II and/orIII are generally from 1:20 to 1:5.

The compositions according to the invention preferably comprise ascompound of formula I a compound of formula Ia ##STR7##

Other preferred compositions comprise a compound of formula Ia, Ib or Icand the compound of formula II and/or III. Of those, compositionscomprising a compound of formula Ia, Ib or Ic and the compound offormula II or III are especially suitable.

The rate of application may vary within wide limits and depends upon thenature of the soil, the type of use (pre- or post-emergence; seeddressing; application to the seed furrow; no tillage application, etc.),the crop plant, the weed to be controlled, the prevailing climaticconditions and other factors determined by the type of use, time of useand target crop. Generally the active ingredient mixture according tothe invention can be applied at a rate of application of from 250 to2500 g, especially from 500 to 1000 g, active ingredient mixture/ha.

In the composition according to the invention, the compound or compoundsof formula I is/are present in a ratio by weight of from 1:100 to1:0.001 with respect to the compound of formula II and/or III.

The mixtures of the compound or compounds of formula I with the compoundof formula II and/or III may be used in unmodified form, that is to sayas obtained in the synthesis, but they are preferably formulated incustomary manner together with the adjuvants customarily employed informulation technology e.g. into directly sprayable or dilutablesolutions, dilute emulsions, wettable powders, soluble powders, dusts,granules or micro-capsules. As with the nature of the compositions, themethods of application, such as spraying, atomising, dusting, wetting,scattering or pouring, are chosen in accordance with the intendedobjectives and the prevailing circumstances.

The formulations, i.e. the compositions, preparations or mixturescomprising the compounds (active ingredients) of formulae I and IIand/or III and, where appropriate, one or more solid or liquidformulation adjuvants, are prepared in a manner known per se, e.g. byhomogeneously mixing and/or grinding the active ingredients with theformulation adjuvants, e.g. solvents or solid carriers. It is alsopossible to use surface-active compounds (surfactants) in thepreparation of the formulations.

Suitable solvents are: aromatic hydrocarbons, preferably the fractionscontaining 8 to 12 carbon atoms, such as mixtures of alkylbenzenes, e.g.xylene mixtures or alkylated naphthalenes; aliphatic and cycloaliphatichydrocarbons, such as paraffins, cyclohexane or tetrahydronaphthalene;alcohols, such as ethanol, propanol or butanol; glycols and their ethersand esters, such as propylene glycol or dipropylene glycol ether;ketones, such as cyclohexanone, isophorone or diacetone alcohol;strongly polar solvents, such as N-methyl-2-pyrrolidone, dimethylsulfoxide or water; vegetable oils and esters thereof, such as rape oil,castor oil or soybean oil; and, where appropriate, also silicone oils.

The solid carriers used, e.g. for dusts and dispersible powders, arenormally natural mineral fillers, such as calcite, talcum, kaolin,montmorillonite or attapulgite. In order to improve the physicalproperties it is also possible to add highly dispersed silicic acid orhighly dispersed absorbent polymers. Suitable granulated adsorptivecarriers are porous types, for example pumice, broken brick, sepioliteor bentonite, and suitable nonsorbent carriers are, for example, calciteor sand. In addition, a great number of pregranulated materials ofinorganic or organic nature can be used, e.g. especially dolomite orpulverised plant residues.

Depending upon the nature of the compound of formula I to be formulated,suitable surface-active compounds are non-ionic, cationic and/or anionicsurfactants having good emulsifying, dispersing and wetting properties.The term "surfactants" will also be understood as comprising mixtures ofsurfactants.

Both water-soluble soaps and water-soluble synthetic surface-activecompounds are suitable anionic surfactants.

Suitable soaps are the alkali metal salts, alkaline earth metal salts orunsubstituted or substituted ammonium salts of higher fatty acids (C₁₀-C₂₂), e.g. the sodium or potassium salts of oleic or stearic acid, orof natural fatty acid mixtures which can be obtained e.g. from coconutoil or tallow oil. Mention may also be made of fatty acid methyltaurinsalts.

More frequently, however, synthetic surfactants are used, especiallyfatty alcohol sulfonates, fatty alcohol sulfates, sulfonatedbenzimidazole derivatives or alkylaryl-sulfonates.

The fatty alcohol sulfonates or sulfates are usually in the form ofalkali metal salts, alkaline earth metal salts or unsubstituted orsubstituted ammonium salts and contain a C₈ -C₂₂ alkyl radical, whichalso includes the alkyl moiety of acyl radicals, e.g. the sodium orcalcium salt of lignosulfonic acid, of dodecyl sulfate or of a mixtureof fatty alcohol sulfates obtained from natural fatty acids. Thesecompounds also comprise the salts of sulfated and sulfonated fattyalcohol/ethylene oxide adducts. The sulfonated benzimidazole derivativespreferably contain two sulfonic acid groups and one fatty acid radicalcontaining 8 to 22 carbon atoms. Examples of alkylarylsulfonates are thesodium, calcium or triethanolamine salts of dodecylbenzenesulfonic acid,dibutylnaphthalenesulfonic acid, or of a condensate ofnaphthalenesulfonic acid and formaldehyde.

Also suitable are corresponding phosphates, e.g. salts of the phosphoricacid ester of an adduct of p-nonylphenol with 4 to 14 mol of ethyleneoxide, or phospholipids.

Non-ionic surfactants are preferably polyglycol ether derivatives ofaliphatic or cycloaliphatic alcohols, saturated or unsaturated fattyacids and alkylphenols, said derivatives containing 3 to 30 glycol ethergroups and 8 to 20 carbon atoms in the (aliphatic) hydrocarbon moietyand 6 to 18 carbon atoms in the alkyl moiety of the alkylphenols.

Further suitable non-ionic surfactants are the water-soluble adducts ofpolyethylene oxide with polypropylene glycol,ethylenediaminopolypropylene glycol and alkylpolypropylene glycolcontaining 1 to 10 carbon atoms in the alkyl chain, which adductscontain 20 to 250 ethylene glycol ether groups and 10 to 100 propyleneglycol ether groups. These compounds usually contain 1 to 5 ethyleneglycol units per propylene glycol unit.

Examples of non-ionic surfactants are nonylphenol polyethoxyethanols,castor oil polyglycol ethers, polypropylene/polyethylene oxide adducts,tributylphenoxypolyethoxyethanol, polyethylene glycol andoctylphenoxypolyethoxyethanol.

Fatty acid esters of polyoxyethylene sorbitan, e.g. polyoxyethylenesorbitan trioleate, are also suitable non-ionic surfactants.

Cationic surfactants are preferably quaternary ammonium salts whichcontain, as N-substituent, at least one C₈ -C₂₂ alkyl radical and, asfurther substituents, unsubstituted or halogenated lower alkyl, benzylor hydroxy-lower alkyl radicals. The salts are preferably in the form ofhalides, methyl sulfates or ethyl sulfates, e.g.stearyltrimethylammonium chloride orbenzyldi(2-chloroethyl)ethylammonium bromide.

The surfactants customarily employed in formulation technology, whichmay also be used in the compositions according to the invention, aredescribed inter alia in "Mc Cutcheon's Detergents and EmulsifiersAnnual", MC Publishing Corp., Ridgewood, N.J., 1981; Stache, H.,"Tensid-Taschenbuch" (Surfactant Handbook), Carl Hanser Verlag,Munich/Vienna 1981; and M. and J. Ash, "Encyclopedia of Surfactants",Vol. I-III, Chemical Publishing Co., New York, 1980-1981.

The herbicidal compositions usually comprise 0.1 to 99%, preferably 0.1to 95%, of an active ingredient mixture of the compound(s) of formula Iwith the compound of formula II and/or III, 1 to 99% of a solid orliquid adjuvant, and 0 to 25%, preferably 0.1 to 25%, of a surfactant.

Whereas commercial products will preferably be formulated asconcentrates, the end user will normally employ dilute formulations.

The compositions may also comprise further auxiliaries, such asstabilisers, e.g. vegetable oils or epoxidised vegetable oils(epoxidised coconut oil, rape oil or soybean oil), anti-foams, e.g.silicone oil, preservatives, viscosity regulators, binders andtackifiers, as well as fertilisers or other active ingredients.

Preferred formulations have especially the following composition(throughout, percentages are by weight):

Emulsifiable Concentrates

active ingredient mixture: 1 to 90%, preferably 5 to 20%

surface-active agent: 1 to 30%, preferably 10 to 20%

liquid carrier: 5 to 94%, preferably 70 to 85%

Dusts

active ingredient mixture: 0.1 to 10%, preferably 0.1 to 5% solidcarrier: 99.9 to 90%, preferably 99.9 to 99%

Suspension Concentrates

active ingredient mixture: 5 to 75%, preferably 10 to 50%

water: 94 to 24%, preferably 88 to 30%

surface-active agent: 1 to 40%, preferably 2 to 30%

Wettable Powders

active ingredient mixture: 0.5 to 90%, preferably 1 to 80%

surface-active agent: 0.5 to 20%, preferably 1 to 15%

solid carrier: 5 to 95%, preferably 15 to 90%

Granules

active ingredient mixture: 0.1 to 30%, preferably 0.1 to 15%

solid carrier: 99.5 to 70%, preferably 97 to 85%

The following Examples further illustrate, but do not limit, theinvention.

FORMULATION EXAMPLES

Mixtures of Compounds of Formulae I and II and/or III (Throughout,Percentages are by Weight)

    ______________________________________    F1. Emulsifiable concentrates                     a)      b)      c)    d)    ______________________________________    mixture of compound(s) of                     5%      10%     25%   50%    formula I with one of the    compounds of formula II and/or III    calcium dodecyl benzenesulfonate                     6%       8%      6%    8%    castor oil polyglycol ether                     4%      --       4%    4%    (36 mol of ethylene oxide)    octylphenol polyglycol ether                     --       4%     --     2%    (7-8 mol of ethylene oxide)    cyclohexanone    --      --      10%   20%    aromatic hydrocarbon mixture                     85%     78%     55%   16%    C.sub.9 -C.sub.12    ______________________________________

Emulsions of any desired concentration can be obtained from suchconcentrates by dilution with water.

    ______________________________________    F2. Solutions     a)      b)      c)    d)    ______________________________________    mixture of compound(s) of                       5%     10%     50%   90%    formula I with one of the    compounds of formula II and/or III    1-methoxy-3-(3-methoxy-propoxy)-                      --      20%     20%   --    propane    polyethylene glycol MW 400                      20%     10%     --    --    N-methyl-2-pyrrolidone                      --      --      30%   10%    aromatic hydrocarbon mixture                      75%     60%     --    --    C.sub.9 -C.sub.12    ______________________________________

These solutions are suitable for application in the form of microdrops.

    ______________________________________    F3. Wettable powders                     a)      b)      c)    d)    ______________________________________    mixture of compound(s) of                     5%      25%     50%   80%    formula I with one of the    compounds of formula II and/or III    sodium lignosulfonate                     4%      --      3%    --    sodium lauryl sulfate                     2%      3%      --     4%    sodium diisobutylnaphthalene-                     --      6%      5%     6%    sulfonate    octylphenol polyglycol ether                     --      1%      2%    --    (7-8 mol of ethylene oxide)    highly dispersed silicic acid                     1%      3%      5%    10%    kaolin           88%     62%     35%   --    ______________________________________

The active ingredient is thoroughly mixed with the adjuvants and themixture is thoroughly ground in a suitable mill, affording wettablepowders which can be diluted with water to give suspensions of anydesired concentration.

    ______________________________________    F4. Coated granules                       a)        b)     c)    ______________________________________    mixture of compound(s) of                       0.1%      5%     15%    formula I with one of the    compounds of formula II and/or III    highly dispersed silicic acid                       0.9%      2%      2%    inorganic carrier  99.0%     93%    83%    (diameter 0.1-1 mm)    for example CaCO.sub.3 or SiO.sub.2    ______________________________________

The active ingredient is dissolved in methylene chloride and thesolution is sprayed onto the carrier, and the solvent is subsequentlyevaporated off in vacuo.

    ______________________________________    F5. Coated granules                       a)        b)     c)    ______________________________________    mixture of compound(s) of                       0.1%      5%     15%    formula I with one of the    compounds of formula II and/or III    polyethylene glycol MW 200                       1.0%      2%      3%    highly dispersed silicic acid                       0.9%      1%      2%    inorganic carrier  98.0%     92%    80%    (diameter 0.1-1 mm)    for example CaCO.sub.3 or SiO.sub.2    ______________________________________

The finely ground active ingredient is uniformly applied, in a mixer, tothe carrier moistened with polyethylene glycol. Non-dusty coatedgranules are obtained in this manner.

    ______________________________________    F6. Extruder granules                     a)       b)      c)    d)    ______________________________________    mixture of compound(s) of                     0.1%     3%      5%    15%    formula I with one of the    compounds of formula II and/or III    sodium lignosulfonate                     1.5%     2%      3%     4%    carboxymethylcellulose                     1.4%     2%      2%     2%    kaolin           97.0%    93%     90%   79%    ______________________________________

The active ingredient is mixed and ground with the adjuvants, and themixture is moistened with water. The mixture is extruded and then driedin a stream of air.

    ______________________________________    F7. Dusts          a)        b)     c)    ______________________________________    mixture of compound(s) of                        0.1%      1%     5%    formula I with one of the    compounds of formula II and/or III    talcum             39.9%     49%    35%    kaolin             60.0%     50%    60%    ______________________________________

Ready-for-use dusts are obtained by mixing the active ingredient withthe carriers, and grinding the mixture in a suitable mill.

    ______________________________________    F8. Suspension concentrates                     a)      b)      c)    d)    ______________________________________    mixture of compound(s) of                     3%      10%     25%   50%    formula I with one of the    compounds of formula II and/or III    ethylene glycol  5%      5%      5%    5%    nonylphenol polyglycol ether                     --      1%      2%    --    (15 mol of ethylene oxide)    sodium lignosulfonate                     3%      3%      4%    5%    carboxymethylcellulose                     1%      1%      1%    1%    37% aqueous formaldehyde                     0.2%    0.2%    0.2%  0.2%    solution    silicone oil emulsion                     0.8%    0.8%    0.8%  0.8%    water            87%     79%     62%   38%    ______________________________________

The finely ground active ingredient is intimately mixed with theadjuvants, giving a suspension concentrate from which suspensions of anydesired concentration can be obtained by dilution with water.

It is often more practical for the compound(s) of formula I and themixing partner of formula I and/or III to be formulated separately andto be brought together only shortly before application in the applicatorin the desired mixture ratio in the form of a "tank mixture" in water.

BIOLOGICAL EXAMPLES Example B1

Post-Emergence Test

In a greenhouse, monocotyledonous and dicotyledonous test plants aregrown in plastic pots containing standard soil and in the 4- to 6-leafstage are sprayed with an aqueous suspension of the test compounds offormula I, prepared from a 25% wettable powder formulation (Example F3,b)) corresponding to a rate of application of 2000 g a.i./ha (500 lwater/ha). The test plants are then grown on in the greenhouse underoptimum conditions. After about 18 days the test is evaluated inaccordance with a scale of nine ratings (1=total damage, 9=no action).Ratings of from 1 to 4 (especially from 1 to 3) indicate a good to verygood herbicidal action. In this test the compounds of formula I exhibita strong herbicidal action. The same results are obtained when thecompounds of formula I are formulated in accordance with Examples F1 andF2 and F4 to F8.

What is claimed is:
 1. A herbicidal composition which comprises at leastone compound of formula I ##STR8## R₂ is methyl, methoxy or --OCHF₂, R₃is methyl or --OCHF₂ andE is ═CH-- or ═N--, with E being ═N-- when R₂ ismethoxy,or an agrochemically acceptable salt of at least one of thecompounds of formula I, and a compound of formula II ##STR9## or anagrochemically acceptable salt of the compound of formula II and/or III,in admixture with one another with the exception of the compositionsconsisting essentially of a) 1- (2-Methoxycarbonyl-phenyl)-sulfonyl!-3-4,6-bis-(difluormethoxy)-pyrimidin-2-yl!-urea and a compound of formulaII and/or III and b) 1- (2-Methoxycarbonyl-phenyl)-sulfonyl!-3-4-methoxy-6-methyl)-triazin-2-yl!-urea and a compound of formula IIand/or III, and c) 1- (2-Methoxycarbonyl-phenyl)-sulfonyl!-3-4,6-(dimethyl)-pyrimidin-2-yl! urea and a compound of Formula II and/orIII.
 2. A composition according to claim 1 which comprises as compoundof formula I a compound of formula Ia ##STR10##
 3. A herbicidalcomposition according to claim 1 which comprises a compound of formulaIa, Ib or Ic and the compound of formula II and/or III.
 4. A herbicidalcomposition according to claim 3 which comprises a compound of formulaIa, Ib or Ic and the compound of formula II or III.
 5. A herbicidalcomposition according to claim 1 which comprises the compound orcompounds of formula I in a ratio by weight of from 1:100 to 1:0.001with respect to the compound of formula II and/or III.
 6. A method ofcontrolling undesired plant growth in crops of useful plants, whichcomprises applying a herbicidally effective amount of a compositionaccording to claim 1 to the cultivated plant or on the locus thereof. 7.A method according to claim 6 wherein the cultivated plant is maize orsoybeans.
 8. A method according to claim 6 wherein the cultivated plantsare treated with the compositions at rates of application of a totalamount of active ingredient of from 0.25 to 2.5 kg per hectare.
 9. Acomposition according to claim 1 which comprises a compound of formulaIb
 10. A herbicidal composition which comprises at least one compound offormula Ia or an agrochemically acceptable salt of the compound offormula II and/or III; in admixture with one another, wherein thecompound of formula Ia is in a ratio by weight of from 1:100 to 1:0.001with respect to the compound of formula II and/or III.
 11. A method ofcontrolling undesired plant growth in crops of maize or soybeans, whichcomprises applying a herbicidally effective amount of a compositionaccording to claim 10 to the cultivated plant or on the locus thereof.12. A method according to claim 11 wherein the cultivated plants aretreated with the compositions at rates of application of a total amountof active ingredient of from 0.25 to 2.5 kg per hectare.